Mental illness surveillance among adults in the United States.

Mental illnesses account for a larger proportion of disability in developed countries than any other group of illnesses, including cancer and heart disease. In 2004, an estimated 25% of adults in the United States reported having a mental illness in the previous year. The economic cost of mental illness in the United States is substantial, approximately $300 billion in 2002. Population surveys and surveys of health-care use measure the occurrence of mental illness, associated risk behaviors (e.g., alcohol and drug abuse) and chronic conditions, and use of mental health-related care and clinical services. Population-based surveys and surveillance systems provide much of the evidence needed to guide effective mental health promotion, mental illness prevention, and treatment programs. This report summarizes data from selected CDC surveillance systems that measure the prevalence and impact of mental illness in the U.S. adult population. CDC surveillance systems provide several types of mental health information: estimates of the prevalence of diagnosed mental illness from self-report or recorded diagnosis, estimates of the prevalence of symptoms associated with mental illness, and estimates of the impact of mental illness on health and well-being. Data from the CDC 2005-2008 National Health and Nutrition Examination Survey indicate that 6.8% of adults had moderate to severe depression in the 2 weeks before completing the survey. State-specific data from the CDC 2006 Behavioral Risk Factor Surveillance System (BRFSS), the most recent BRFSS data available, indicate that the prevalence of moderate to severe depression was generally higher in southeastern states compared with other states. Two other CDC surveys on ambulatory care services, the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey, indicate that during 2007-2008, approximately 5% of ambulatory care visits involved patients with a diagnosis of a mental health disorder, and most of these were classified as depression, psychoses, or anxiety disorders. Future surveillance should pay particular attention to changes in the prevalence of depression both nationwide and at the state and county levels. In addition, national and state-level mental illness surveillance should measure a wider range of psychiatric conditions and should include anxiety disorders. Many mental illnesses can be managed successfully, and increasing access to and use of mental health treatment services could substantially reduce the associated morbidity.